The aerosol industry has successfully employed fluorocarbons as propellants in aerosol containers. Fluorocarbons are well suited to this purpose since they are usually non-flammable, non-toxic and odorless. Use of fluorocarbons as propellants has, however, diminished because of the adverse environmental impact they are believed to have on the ozone layer of our atmosphere. As a consequence it has become desirable to find substitutes for the fluorocarbon propellants. Saturated hydrocarbons have been used to this end. Best suited are the low boiling paraffinic hydrocarbons such as, for example, propane, isobutane and pentane.
One disadvantage associated with the use of saturated hydrocarbons is the presence of impurities that impart undesirable odors. Although these impurities are usually present only in very small amounts their odorous presence is typically very perceptible. These odor-causing impurities must be removed before the hydrocarbon is used as a propellant. The odor-causing impurities include sulfides, mercaptans, olefins and oxygenated olefins. Removal of olefin impurities, for example, can be a formidable task since quantities as low as 10 parts per million (ppm) (0.001 wt %) are known to cause an unacceptable odor.
This invention provides a process for the deodorization of such hydrocarbon propellants. More broadly, the process is applicable to the deodorization of hydrocarbon feedstocks containing odor-causing impurities.